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Anthropometric indices

BMI Waist W/H ratio Skinfold thickness. Anthropometric indices. Densitometry Total body water (TBW ) Dual energy X-ray absorptiometry Bioelectrical impedance ( Bioimpedance ). Measurements of body composition. Computed tomography (CT) imaging Magnetic resonance (MR) imaging.

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Anthropometric indices

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  1. BMI • Waist • W/H ratio • Skinfold thickness Anthropometric indices

  2. Densitometry • Total body water (TBW) • Dual energy X-ray absorptiometry • Bioelectrical impedance (Bioimpedance) Measurements of body composition

  3. Computed tomography (CT) imaging • Magnetic resonance (MR) imaging Measurements of fat distribution

  4. Measurements of body fat that are expensive and require special equipment and highly trained personnel include: • Measurements that are simple, cheap and appropriate for routine use include: • Underwater weighing • Bioelectrical impedance • Computerized topography • BMI • waist circumference • Hip circumference • Waist-to-hip ratio • Skin fold thickness

  5. Height • Weight • Body Mass Index (BMI) [weight/height]2 • Kg/m2 • (lb/in)2 x 703 • Distribution of body fat • Waist-hip ratio (WHR) • Waist circumference Anthropometrics in Obesity

  6. Objective with high specificity & sensitivity • Readings are numerical & gradable on standard growth charts • Readings are reproducible. • Non-expensive & need minimal training Advantages of anthropometry

  7. Inter-observers errors in measurement • Problems with reference standards, i.e. local versus international standards. • Arbitrary statistical cut-off levels for what considered as abnormal values. Limitations of Anthropometry

  8. Express weight adjusted for height • Body mass index (BMI) = weight (kg)/height (m)2 What is BMI?

  9. 70 • Age • Gender • Race Women 60 Men 50 40 Body Fat (%) 30 20 10 0 Relationship Between BMI and Percent Body Fat in Men and Women 50 60 0 10 20 30 40 Body Mass Index (kg/m2) Adapted from: Gallagher et al. Am J Clin Nutr 2000;72:694.

  10. BMI and Body fat%

  11. low-cost and easy to use for health professionals for assessing individuals • Reliable • commonly used to determine desirable body weights and allows people to compare their own weight status to that of the general population Advantages of using BMI

  12. Correlates well with the amount of body fat as measured by more complex techniques • Predicts dangers associated with obesity; as BMI increases the risk for diseases increases • A useful screening tool to use at the population level and, because it is universally accepted, BMI reference data is available for many different populations • Can be used for selection of therapy Advantages of using BMI

  13. It does not distinguish the accumulation of muscle (lean body mass)from the accumulation of adipose tissue(body fat) • It varies with age and sex in those <18 years • Different cut points in different ethnic groups Disadvantages of BMI

  14. Weight loss induced by exercise is associated with smaller losses of lean tissue (which is denser than fat), compared with dietary restriction alone. • Thus, weight and BMI may change little during an exercise program, even though significant loss of fat may occur Disadvantages of BMI

  15. Classification BMI (kg/m2) Risk • Underweight <18.5 Increased • Normal 18.5–24.9 Normal • Overweight 25.0–29.9 Increased • Obese I 30.0–34.9 High • II 35.0–39.9 Very high • III 40 Extremely high • Additional risks: • Large waist circumference (men >40 in; women >35 in) • 5 kg or more weight gain since age 18–20 y • Poor aerobic fitness • Specific races and ethnic groups BMI-Associated Disease Risk Clinical Guidelines on the Identification, Evaluation, and Treatment of Overweight and Obesity in Adults—The Evidence Report. Obes Res 1998;6(suppl 2).

  16. BMI cut-points of 25 (overweight) and 30 (obesity) recommended by expert committees • For adults, the Expert Committee proposed classification of BMI with the cut-off points 25, 30 and 40…This classification is based principally on the association between BMI and mortality. 1995 WHO expert committee report

  17. Relation between mortality and BMI Data from Lew EA: Mortality and weight: insured lives and the American Cancer Society studies. Ann Intern Med103:1024-1029, 1985.

  18. Android Gynoid

  19. What is the power of waist circumference to predict adverse cardio-metabolic outcomes? • How does the predictive power of waist circumference compare with that of BMI? Importance of fat distribution

  20. Increased Cardiometabolic Risk Abdominal Obesity Dyslipidemia Hypertension Glucose Intolerance Insulin Resistance Health threat from abdominal obesity is largely due to intra-abdominal obesity Intra-Abdominal Adiposity Adapted from Eckel et al 2005

  21. Visceral Fat:The Critical Adipose Depot Back

  22. Immediately below the lowest rib • At the narrowest waist1 • Midpoint between the lowest rib and the iliac crest2 • Immediately above the iliac crest3,4 Waist CircumferenceMeasurement Sites • Anthropometric Standardization Reference Manual • World Health Organization (WHO) • National Institutes of Health (NIH) • National Health and Nutrition Examination Survey (NHANES)

  23. Place a measuring tape, held parallel to the floor, around the patient’s abdomen at a designated level. • The tape should fit snugly around the waist without compressing the skin • Take the measurement at the end of a normal expiration How to Measure Waist Circumference Adapted from Grundy SM, et al. Circulation. 2005;112:2735-2752.

  24. BMI and WC are highly correlated ,typically with r values in range of 0.85-0.95

  25. CT scans matched for BMI and total body fat Visceral obesity Fat mass: 19.8 kg VFA: 155 cm2 Similar BMI Subcutaneous (sc) obesity Fat mass: 19.8 kg VFA: 96 cm2 Visceral vs subcutaneous adiposity White = VFA Black = sc fat Després J-P. Eur Heart J Suppl. 2006;8(suppl B):B4-12.

  26. Lean MEJ, Han TS, Morrison CE. Waist circumference as a measure for indicating need for weight management. BMJ 1995;311:158–61. Randomly recruited 904 men and 1014 women, aged 25 to 74 years, from the general population of north Glasgow between January and August 1992, excluding only those who were chair bound. WC cut points

  27. BMI as Gold Standard Using in ATPIII & EGIR

  28. It has been proposed that waist measurement alone can be used to assess obesity, and two levels of risk have been identified MALES FEMALE LEVEL 1 > 94cm > 80cm LEVEL2 > 102cm > 88cm Waist circumference

  29. Level 1 is the maximum acceptable waist circumference irrespective of the adult age and there should be no further weight gain. • Level 2 denotes obesity and requires weight management to reduce the risk of type 2 diabetes & CVS complications. Waist circumference/2

  30. Population Group Waist Circumference (Cm) Men Women USA (NCEP ATP III) >102 >88 European >94 >80 South Asian/ >90 >80 Chinese Japanese >90 >85 Metabolic Syndrome: Refined Criteria (IDF)

  31. Country Outcome Age Cut off P.Y. Brazil HTN ----- M:87 F:80 2009 Australia CVD mortality 20-69 M:96 F:80 2007 Japan CVD ≥ 40 M:90 F:80 2009 Thailand CHD 35-59 M:82 2007 China* CVD risk 18-93 M:83-88F:76 2007 Iran CVD ≥ 40 M:94.5 F:94.5 2009 Cohort Studies to determine WC cutoff

  32. Archives of Iranian Medicine, Volume 13, Number 3, May 2010

  33. Is measured at the point of greatest circumference around hips & buttocks to the nearest 0.5 cm. • The subject should be standing and the measurer should squat beside him. • Both measurement should taken with a flexible, non-stretchable tape in close contact with the skin, but without indenting the soft tissue. Hip Circumference

  34. High risk WHR= >0.80 for females & >0.90 for males i.e. waist measurement >80% of hip measurement for women and >95% for men indicates central (upper body) obesity and is considered high risk for diabetes & CVS disorders. • A WHR below these cut-off levels is considered low risk. Interpretation of WHR

  35. Median 6.6-years changes in waist circumference

  36. Median 6.6-years changes in abdominal obesity

  37. A skinfold thickness (SFT) is the double thickness of the epidermis, underlying fascia and subcutaneous fat, when the tissues are pinched between measuring calipers • Measurements are usually made at four sites: biceps, triceps, subscapular and suprailiac. • Using sex- and age-dependent, population-based linear regression equations, the sum of these values (in mm) can be used to estimate total body fat Skinfold Thickness

  38. Measures double thickness of skin and subcutaneous fat • Advantages: • inexpensive • fast • portable • large database Skinfold Thickness

  39. Major limitation is considerable observer error • This limits the usefulness of this technique outside research environments • Skinfold thickness affected by factors other than amount of fat • exercise increases skin thickness • dehydration reduces skin thickness • edema increases skin thickness • dermatitis increases skin thickness • Poorly predicts visceral fat Limitations

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